Screw-threading machine



(No Model.) 3 Sheets-Sheet l.

E. C'. MILLER.

SCREW THREADING MACHINE. No. 402,759. Patented May '7, V1889.

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(No Mgael.) 's sheets-.sheet 2.

1:". C. MILLER.

SCREW THRBADING MACHINE. No. 402,759. Patented May 7, 1889.

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(No Model.)

F. c. MILLER.

` SCREW THREADING .MA'GHINB. No. 402.759. Patentedmay 7, 1889.

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"A UNITED STATES PATENT GEEICE.

FREDRICK C. MILLER, OF NEWPORT, KENTUCKY.

SCREW-TH READING MACHINE.

SPECIFICATION forming part 0f Letters Patent N0. 402,759, dated May 7, 1889. Application led June 30, 1887. -Serial No. 243,012. (No model.)

To all whom it may concern:

Be it known that I, FREDRICK C. MILLER, a citizen of the United States, residing at Newport, in the county of Campbell and State of Kentucky, have invented certain new and useful Improvements in Screw-Cutting Machines, of which the following' is a full, clear, and eX- act specification.

The object of my invention is to cut screws with a perfectly uniform thread, which is not done when the die does its own feeding while cutting, and in many instances it is not possible to out a screw on these machines that can be used for lack of accuracy in the pitch of the thread, especially when the screw is to pass through a deep nut, therefore necessitating the cutting of screws on lathes, which is a long and tedious operation.

It is well known in practice that although a die may be made with a fixed pitch of thread, yet where such a die is used to cut a screw on a rod the pitch of thread on the rod will often vary both ways from that of the die-that is, sometimes it will be coarser and at other times nner.

The invention consists in certain features of novelty which are hereinafter particularly pointed out in the claims, being first fully described With reference to. the accompanying drawings, in which- Figure I is a vertical longitudinal section of the improved screw-cutting machine, the section being taken on the line I I, Fig. II. Figs. II and III are elevations of the respective ends of the machine. Fig. IV is an ele- `vation of the cutter-head, showing the means for securing the cutters in place. FigJV is an end elevation showing a modification in the means for changing the speed of the feedscrew.

l represents the bed of the machine, supported by suitable legs, 2, and having upon its upper sidetwo parallel anges, 3, grooved on their inner faces for the reception of tongues formed on the carriage 4, which carries the clamp for holding the blank to be Upon the upper side of the carriage 4, and transversely to the plane in which it moves, isa dovetail ange, 5, which engages corresponding grooves formed in the under sides of a pair of opposing jaws, 6.

Each of these jaws is provided with a screwthreaded perforation parallel with the dovetail 5 for the passage of ascrew, 7 the threads of which are pitched in opposite directions from the center, a hand-wheel, 8, being securedto one end thereof, whereby to turn it and cause the jaws 6 to move in opposite directions, either toward or from each other, according to the direction in which the screw is turned. The opposite faces of each of the jaws 6 are cut away, so as to form cavities or recesses comprising something over one hundred and eighty degrees of a circle, said recesses being so situated that they are intersected by the plane of that face of the jaw which is presented toward the opposite jaw. Fitting snugly in each of these recesses is a circular die, 9, which is revoluble upon a center, lO, so that anyone of a series of notches, ll, cut in its periphery may be presented t0- ward the opposite jaw 6. The recesses are such that the planes of all the dies 9 shall be parallel and the dies in the opposite jaws -6 shall come together in pairs, so as to bite and hold between them the blank to be threaded.

All of the dies 9 are precisely alike, and, as shown in Fig. 3, the notches 0f each disk are of different sizes, all being equilateral right angles. This is for the purpose of clamping the square heads of bolts, notches of large or small size being used, according to the size of the head. It is obvious that these dies may be replaced by others having notches of different sizes or shapes for meeting the requirements of any particular case.

The carriage is provided on its under side with a hollow boss or stud, 12, through which passes a cylindrical stem, 13, which carries at its lower extremity a clamp consisting of a block, 14, perforated for the passage of a cylindrical rod, 15, and split on one side, so as to form spring-jaws I6 17, as shown in Fig. 3.

1S is a screw whose cylindrical shank passes through a perforation through the carriage 4, its head resting upon the top of the carriage, so as to be readily accessible. The lower portion 0f this screw is of smaller diameter than the upper portion, so that a shoulder is formed which bears upon the top side of the jaw 16, said jaw being perforated for the free passage of the reduced portion of the stem, which is IOO ` ard 29, to the feed-pinion 21.

screw-threaded and engages a screw-threaded aperture formed through the jaw 17.

It will be apparent that by turning the screw 18 the jaws 1G 17 will be moved either toward or from each other, and in so doing the aperture through the block correspondingly decreased or increased in size, thereby clamping or freeing the rod 15. W'hile in operation the rod l5 is iirmly clamped in the block 14, and the carriage partakes of the longitudinal movement which is imparted to the rod by the mechanism now to be described.

19 is a screw, (hereinafter called the feedscrew,) the inner end of which is provided with a socket for the reception of the end of the rod l5, both rod and screw being perforated for the passage of a pin or key, 20, where- 4 by the screw and rod are held firmly together,

vsleeve 23 by an annular bearing-plate, 25,

which is secured to the extremity of said hub and projects over the extremity of said sleeve. It is held against similar movement in the other direction by reason of the fact that the pinion 21 (which, as before stated, is integral with its hub) bears against the iange 24.

The feed-pinion may be internally screw threaded, if desired, for engaging the threads of the feed-screw 19; but it is preferred to cut these threads in a separate bushing, 26, having a flange, 27, which is secured to the face of the pinion 21 by screws.

It will be seen that by rotating the feedpinion 2l, it being held against longitudinal motion, the screw 19 and rod 15` (both being held against rotary motion) will be moved longitudinally, of which motion the carriage carrying the .clamp for holding the blank while being cut partalres.

To make screw-threads of different pitch,

feed-screws of dierent pitch, which may be replaced one by the other, according to the pitch of thread desired, are used.

2S represents the spindle of the machine, which is hollow and turns in the bearings at the upper extremities of standards 29, rising from the base 1. Between these bearings the spindle 28 is provided with a cone-pulley, 30, whereby the said spindle is driven, its motion being transmitted through the medium of a pinion, 31, secured to one of its extremities, and an idler, 32, journaled to the stand- Thus it will be seen that the entire machine may be operated by a single belt. The cutter-head is secured to the end of the spindle 28 remote from the pinion 31, for which purpose the said spindle is formed with an offset, 33, within which is an enlarged annular socket for the reception of the reduced portion of the die-stock 34, whereby the inner surfaces of said die-stock and mandrel are brought iiush with each other.

The die-stock 34 is provided with an annular rabbet-or, in other words, the bore through it is enlargedfor the reception of the dies 35, which are of the shape shown in Fig. 4 that is to say, the back of each die is constructed on a circle of equal radius with the interior of the annular rabbet in which the dies fit, while the cutting-teeth are formed at 36 concentrically with the axis of the spindle. Cavities of something less than semicircular shape are formed in the opposing straight faces of the dies 35, as at 37, for embracing the Shanks of screws 38, which are tapped into the stock 34. These screws hold the dies in the annular rabbet in the die-stock by reason of the fact that their heads bear against the outer faces of the dies, and said heads may be countersunk or not, as desired. It is preferred to countersink` them and to form the countersink partly in each of the dies and partly in the stock, so as to more effectually resist the rotary movement of the dies within the annular rabbet in which they are seated.

To more efectually hold the dies against movement, a pair of jam screws, 39, are tapped into the stock 34 at diametrically-opposite points, so as to bear against the backs of the dies about mid-length. By these screws 39 the dies are held firmly against the shanks of the screws 38.

In Fig. 5 I have shown a modification in the mechanism for varying the speed with which the feed-screw is moved longitudinally, in which modification the separate internallyscrew-threaded bushing shown at 26 in Fig. 1 is dispensed with and the threads are cut directly into the body of the feed-pinion 21, which in other respects may be constructed as already described.

IOO

IIO

Instead of the single idler 32 shown in f Fig. 1 for transmitting motion from the pinion 31 to the pinion 21, according to the modification now under consideration, a series of pinions is employed, arranged as follows: 40 is a pinion turning on a spindle suitably supported by the frame of the machine and gearing directly with the pinion 31 on the spindle 28. Fixed to the pinion 40 so as to be removable independently thereof is a pinion, 41, which gears directly with a pinion, 42, journaled in a radius-bar, 43, which swings on a center coincident with the axis of the pinion 21. Projecting from the side of this radius-bar is a curved arm, 44, having a slot formed therein concentrically with the axis of motion of said bar for the passage of a screwbolt, 45, which is tapped with the standard 29, and whose head, or a washer placed beneath said head, bears against said arm 44, for holding the radius-bar in any position in which it may be set. The shaft or stud toward and from the axis of the pinion 21 by reason of a slot formed in the radius-bar. With this arrangement the velocity with which the pinion 21 is rotated, and the consequent Velocity of the longitudinal movement of the feed-screw, may be changed and made to bear any desired relation to the velocity of the spindle 28 by simply substituting for the pinion 41 or the pinion 42, or both of them, other pinions of different diameters.

Having thus described my invention, the following is whatI claim as new therein and desire to secure by Letters Patent:

1. A screw-cutting machine consisting, essentially, of the die-holder, screw-cutting die contained therein, the clamp by which the rod to be threaded is held by one end, the carriage permitting relative longitudinal movement between the rod and die, the feed-screw and nut corresponding in pitch with the screw to be produced and imparting positive feed movement, the means for connecting the feed-screw and nut to the carriage and dieholder, respectively, and gearing' communicating corresponding rotation from the screwcutting to the feeding devices, substantially as herein described.

2. The combination, with the carriage 4, the rod 5, and feed-screw and nut and connecting-gear for moving said rod longitudinally, of the block 14, perforated for the passage of the rod 15, and having the spring-jaws 16 17, and the screw 18, for closing said jaws, substantially as set forth.

3. The combination, with the carriage 4, having the hollow stud 12, and the longitudinally-movable rod 15, of the stem 13, fitting said hollow stud, and means at the lower extremity of said stem for engaging the. rod, substantially as set forth.

4. The combination of the carriage, rodholding clamp, die-holder, feed-screw and nut,

means for connecting the feed-screw and carriage, and connecting-gearing for imparting equal rotation to the screw-cutting and feeding mechanism and relative longitudinal motion to the parts, as described and shown.

5. The combination of the carriage, the feed-screw having the socket in the extremity thereof, nut and gearing for imparting longitudinal motion to said screw, and the feedrod having one extremity inserted in said socket and adj ustably secured to the carriage, substantially as set forth.

6. The combination of the carriage, the feed-screw adjustably secured thereto, the feed-pinion having a removable internallyscrew-threaded bushing, and gearing' for ro tatin g said feed-pinion, substantially as set forth.

7. The combination, with the carriage, the feed-screw, and the internally-screw-threaded feed-pinion having the hub 22, of the annular bearing-plate secured to the end of said hub for holding it in place, substantially as set forth.

8. The combination, with the carriage, the feed-screw, and the intern ally-screw-threaded feed-pinion having the hub 22, of the bearingsleeve, and the annular bearing-ring secured to the end of the hub and projecting over the end of the bearing-sleeve, substantially as set forth.

9. The combination, with the carriage, the feed-screw, and the internally-screw-threaded feed-pinion having the hub 22, of the bearingsleeve 23, having the flange 24, secured to the frame of the machine, and the annular bearing-plate secured to the extremity of the hub 22 and projecting over the bearing-sleeve, substantially as set forth.

FREDRIOK C. MILLER.

Witnesses:

E. C. REMME, FRANK M. BROWN.

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